Prognostic value of circulating tumor cells with podoplanin expression in patients with locally advanced or metastatic head and neck squamous cell carcinoma

Background Podoplanin (PDPN) is a prognostic factor for head and neck squamous cell carcinoma (HNSCC). However, PDPN expression in circulating tumor cells (CTCs) and its prognostic value are not clear. Methods The PowerMag system was used to enumerate CTCs from 53 patients with HNSCC prechemotherapy and 61 healthy donors. PDPN expression was determined by immunofluorescence staining. Results were correlated with clinicopathological parameters and clinical outcome, such as patient survival by receiver operating characteristic (ROC) and univariate and multivariate analyses. Results PDPN was expressed in a subset of CTCs. Both EpCAM-positive CTC and PDPN-positive CTC counts were statistically different between the disease and nondisease groups (p <.0001) with no prognostic value. After a median follow-up of 10.5 months (range, 6.6-18.5 months), the PDPN-positive/EpCAM-positive CTC ratio >20% was a significant prognostic factor for death within 6 months (p =.011) and was correlated with poor progression-free survival (p =.016) and overall survival (p =.015). Conclusion PDPN-positive/EpCAM-positive CTC ratio is a prognostic factor and defining the ratio in patients with HNSCC might be valuable to clinical management.